The study looked at five different types of onions grown in Ontario, Canada and found that Ruby Ring onions were the best at combating cancer cells. Red onions had been known to help with heart problems and diabetes because they had an abundance of quercetin. Now, they’ve been found to be rich in anthocyanin.

“We found onions are excellent at killing cancer cells,” said Abdulmonem Murayyan, lead author, in a press release. “Onions activate pathways that encourage cancer cells to undergo cell death. They promote an unfavorable environment for cancer cells and they disrupt communication between cancer cells, which inhibits growth.”

Their research tested how onions reacted with colon cancer cells as well as breast cancer cells, and they excelled at both.

Murayyan wasn’t surprised to find that red onions would be the best type of onion to help fight cancer.

“Anthocyanin is instrumental in providing color to fruits and vegetables, so it makes sense that the red onions, which are darkest in color, would have the most cancer-fighting power,” said Murayyan.